P0027
Exhaust Valve Control solenoid Circuit Range/Performance Bank 1P0027 is a generic OBD-II powertrain diagnostic trouble code: Exhaust Valve Control solenoid Circuit Range/Performance Bank 1. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0027 means
P0027 is set when the powertrain control module (PCM) detects that the exhaust valve control solenoid circuit on Bank 1 (the cylinder bank containing cylinder #1) is operating outside its expected range. Bank 1 is the side of the engine containing the number-one cylinder on V-type and flat engines. The code belongs to the Variable Valve Timing (VVT) / Variable Camshaft System (VCS) family, where oil-fed hydraulic actuators shift camshaft phasing under solenoid control to optimise power, torque, and emissions across the RPM range.
The PCM continuously monitors actuator feedback voltage and commanded position. P0027 triggers when the measured voltage deviates more than approximately 10% from the reference voltage for the exhaust camshaft actuator on Bank 1, or when the actual camshaft position fails to follow the commanded target within a defined time window. Because the solenoid relies entirely on pressurised engine oil to move the vane-type phaser, oil quantity and quality are the most frequent root causes — far ahead of electrical or mechanical failures. Continued operation with this fault active causes the exhaust cam to remain stuck in a fixed timing position, reducing power at certain RPM ranges and increasing tailpipe emissions.
Common causes
Most-frequently reported root causes when P0027 is logged.
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1
Low engine oil level — the most frequent cause; insufficient oil starves the VVT actuator of hydraulic pressure
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2
Low or degraded engine oil pressure due to a worn oil pump or blocked oil pickup screen
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3
Wrong engine oil specification (viscosity or grade) preventing proper solenoid and actuator operation
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4
Open or short circuit in the exhaust valve control solenoid wiring harness on Bank 1
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5
Corroded or loose electrical connectors at the solenoid or PCM
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6
Faulty or mechanically stuck exhaust valve control solenoid (internal coil failure or sludge binding)
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7
Sludge or carbon deposits blocking VVT oil passages or the actuator vane
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8
Faulty PCM (rare) — internal driver failure on the solenoid control channel
Symptoms drivers notice
How to diagnose P0027
A typical diagnostic flow when this code is present.
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1
Check engine oil level on the dipstick; inspect for leaks and top up to the correct mark, then clear the code and road-test to see if it returns
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2
Verify the correct oil viscosity and grade is fitted; replace with manufacturer-specified oil if in doubt, as incorrect oil can prevent proper hydraulic actuator operation
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3
Perform an oil pressure test; low pressure at idle or under load points to a worn pump, blocked pickup, or excessive bearing clearance
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4
Using a DVOM, unplug the solenoid connector and measure coil resistance — compare against OEM spec (typically 6–15 Ω); an open or shorted coil requires solenoid replacement
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5
Inspect the wiring harness from the PCM to the Bank 1 exhaust solenoid for chafing, corrosion, or broken pins; check reference voltage and ground continuity
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6
With a scan tool, command the solenoid on/off and observe live actuator feedback; a commanded change with no position response suggests a mechanical fault in the actuator or blocked oil passages
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7
If oil passages are suspected blocked, perform an engine oil flush and retest before condemning the actuator
Related powertrain codes
Frequently asked questions
Can I drive my car with a P0027 code?
Short distances are possible since the vehicle usually remains driveable, but the fault reduces engine performance and increases emissions. Prolonged driving risks wear to the actuator if oil pressure is the cause — address it promptly.
Will low oil level really trigger P0027?
Yes — low oil is by far the most common cause. The VVT solenoid and actuator depend entirely on pressurised engine oil. Even 1–2 quarts low can drop oil pressure enough to set range/performance codes.
How do I know if the solenoid itself is bad versus just dirty?
Remove the solenoid and inspect the filter screen for sludge. Clean the screen, reinstall, and retest. If the fault persists after confirming good oil pressure and clean passages, coil resistance measurement will confirm an internal solenoid failure.
Is P0027 the same fault on every car make?
The generic OBD-II definition is universal, but the threshold values, solenoid design, and oil passage layout vary by manufacturer. Always consult make-specific service data for exact resistance specs and freeze-frame parameters.
Disabling P0027 in software
RaceTune can permanently disable P0027 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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